an apparatus for visual signaling with lights or mechanically moving arms
Any equipment used for visual signalling by means of flags, lights, or mechanically moving arms, which are used to represent letters of the alphabet, or words.
send signals by or as if by semaphore
convey by semaphore, of information
To signal using, or as if using, a semaphore, with the implication that it is done nonverbally.
The word semaphore comes from French, which borrowed it from Ancient Greek words meaning "sign" and "bearer." Originally, it referred to a signaling system that uses visible signs or tokens to communicate.